Elastic link straps



Dec. 3, 1963 E. wEiss ELASTIC LINK STRAPS ori inal Filed July 19, 195 s gang- TOR. I

United States Patent ()fiFice 3.,ll2fifid Patented Dec. 3, 1953 3,112,596 ELASTIC LINK STRAPS Erwin Weiss, Berghausen, Baden, Germany, assignor to Rodi & Wienenberger A.G., Pforzheim, Germany Continuation or application Ser. No. 598,915, July 19,

1956. This application Jan. 8, N62, Ser. No. 167,464

Claims priority, application Germany duly 23, 1955 7 Claims. (Cl. 59-7?) This application is a continuation of my co-pending application Serial No. 598,915, now abandoned, filed July 19, 1956.

The present invention relates to improvements in elastic straps or bracelets which consist of main link elements and intermediate connecting elements which are resiliently connected to each other.

It is an object of the present invention to provide an elastic strap in which the main link and intermediate connecting el ments as seen from the narrow sides of the strap are disposed in a zigzag arrangement relative to each other and are pivotaily and resiliently connected with each other so that, by such resilient pivotal movement, the individual main link elements tend to engage with each other so as to contract the strap to the shortest possible length, while, when the strap is being expanded, the link and connecting elements are pivoted apart, thereby resiliently increasing the distance between the individual link elements so that the strap, when used, for example, as a bracel t or a Watch strap, will adapt itself to the size of the wrist or arm on which it is worn.

Another object of the invention is to provide an elastic strap in which the individual main link elements consist of integrally connected twin or double links forming two layers in different horizontal planes.

A further object of the invention is to provide a new and improved spring construction for resiliently pivoting the individual link and connecting elements of the strap relative to each other.

A further object of the invention is to provide an elastic strap, the resiliency of which is obtained without any separate springs and merely by the self-resiliency of its link members.

A preferred feature of the present invention consists in providing the individual elements in the form of hollow casings which are elongated in the longitudinal direction of the strap but are individually disposed at an oblique angle to the wrist or arm on which the strap is worn. These casings are split apart at one side and one of the free ends which is thus formed is extended into the opposite part of the casing, the free end of which engages over the first free end. The casings are bent so that at least the extended end coming from one part of the casing and projecting into the free end portion of the opposite part forms a spring arm and exerts a spring pressure upon such free end portion, or that both the extended end, as well as the overlapping end portion exert a spring pressure in a direction toward each other. In one preferred embodiment of the invention, the connecting members are made in the form of a rectangular bracket, one crossarm of which is pivotally mounted in the part of the casings opposite to that in which the extended spring end is disposed, while the opposite crossarm is disposed within the opposite part of the adjacent casing and between the mentioned spring arm and the overlapping end. This latter crossarm of the connecting bracket is preferably of a flat shape so that the spring arm and possibly also the overlapping end portion of the casing will exert the greatest possible lever action thereon. This end of the connecting bracket is connected to the pivoting end thereof by a pair of side arms which extend from one to the adjacent casing along the outer ends thereof in the longitudinal direction of the strap. However, since these connecting brackets likewise extend from the lower portion of one casing to the upper portion of the adjacent casing, their general position is likewise oblique with respect to the supporting surface, ie the wrist or arm of the wearer. The fiat bracket arm may either extend continuously across the main links from one side arm to the other, or it may consist of a pair of such flat arms which are extending from the side arms sufiiciently inwardly and into the open ends of the link casings so that the spring arm, and possibly also the overlapping end portion of the links, can exert their full spring pressure thereon. in this case, the pair of flat arms are securely retained within the link casings due to the fact that the pivotal end of each connecting bracket extends within and entirely across the casings from one side arm of the bracket to the other, and thus also maintains the inwardly extending fiat arms in their proper position within the casings. Obviously, instead of extending the pivotal part of the connecting brackets entirely across and within the casings and making the flat bracket arm discontinuous, as just described, the fiat bracket arm may form the continuous cross member, while the pivot part of the bracket may be in the form of a pair of pivot pins extending from the side arms into each link casing.

Furthermore, according to the invention, the opposite side arms of the connecting brackets may be extended or enlarged so as to cover completely the open ends of the link casings.

It is still another object of the invention to provide an elastic strap of the type as described and to be used particularly as an article of jewelry, such as a bracelet, or as a watch strap, the upper or ornamental surface of which appears to form a substantially unbroken surface when the strap is in the contracted or released position. In one embodiment of the invention in which the link casings each consists of two substantially cylindrical parts which are obliquely disposed to each other and integrally connected with each other, such unbroken upper or ornamental surface of the strap when seen from the narrow sides thereof forms an undulating line, while in the second embodiment using substantially rectangular casings which are likewise bent so that the upper and lower parts thereof are in an oblique or oifset position to each other, the upper unbroken ornamental surface of the strap when contracted is smooth and flat. Obviously, both embodiments may be easily modified in shape, for example, by making the link casings of the first embodiment of a more oval or even angular shape, or by making the link casings of the second embodiment, and particularly the upper surface thereof, of a curved or rounded shape.

Thus, it will be understood that by clamping the flat crossarms of the connecting brackets between the spring arm and the overlapping arm of the main links, each link will tend to pivot toward the adjacent link. Since the wall portions of the links thus themselves form the resilient elements, no separate springs will be required to act upon the pivoting connecting brackets. This means a considerable saving in material as well as in the labor usually required in installing the separate springs in the link casings. Thus, the entire construction of the strap is simplified since it consists of no more than two different kinds of parts, namely, the main links and the connecting brackets.

Although the self-resiliency of the main links constitutes an important feature of the present invention in order to obtain the desired resiliency of the strap, separate springs may also be mounted within the links so as to act upon the connecting brackets. In such case, the separate springs may either be provided to augment the spring action which is exerted by the mentioned spring arms of the links themselves, or these spring arms may be omitted entirely and be replaced by such separate springs which are mounted within the link casings.

Another considerable advantage of the new elastic strap is the fact that its total length may be easily shortened or lengthened since the connecting elements may be inserted and locked into or unhooked from the main links by a carbinelike movement against the spring action of the respective link portions.

Further objects, features, and advantages of the present invention will be apparent from the following detailed description thereof, particularly when read with reference to the accompanying drawings, in which:

FIG. 1 shows a cross section through an elastic strap according to one preferred embodiment of the invention in the expanded position, such section being taken along line 1-1 of FIG. 2;

FIG. 2 shows a cross section taken along line 2-2 of FIG. 1;

FIG. 3 shows a cross section of an elastic strap according to a second embodiment of the invention in the expanded position, such section being taken along line 33 of FIG. 4; while FIG. 4 shows a cross section taken along line 4-4 of FIG. '5.

Referring to the drawings, and first particularly to FIGS. 1 and 2, the new elastic strap or bracelet according to the first embodiment of the invention consists of a plurality of hollow main link elements a of substantially cylindrical shape and extending in a direction transverse to the longitudinal direction of the entire strap and intermediate connecting elements 7. These cylindrical link elements a, as seen individually are split at one side, so that each of them thus has substantially the cross-sectional shape of the letter 0. Each two adjacent O-shaped members are turned so that their open ends face each other, and form an interconnected pair a and a" by being integrally connected to each other at one of the opposite open ends of each C. This connecting portion b forms a rounded trough-shape. As shown particularly in FIG. 1, the other free and inwardly curving end 2 of the upper member a" curls over the free end of the lower member a which, for this purpose, after curving inwardly, is extended, and such extended portion d is bent outwardly at toward the upper member a" and projects like an arm into the open end thereof. The lower member a including its straight arm d is bent so as to have an initial spring tension which tends to turn the arm d in the clockwise direction so that the latter will rest under pressure against the inside of the end portion e of the upper member a". This overlapping end portion e may also exert a spring pressure inwardly and toward the arm d.

Each intermediate connecting element f which connects the adjacent pairs of cylindrical member a, a" with each other is of substantially rectangular frarnelike shape, and the two short arms g of which may for example, be of curved shape like a sickle, the wider ends of which are connected by a cylindrical member it, while the narrower ends thereof are connected by a fiat bar i. The cylindrical member h of each intermediate connecting element 1 is pivotally mounted Within the lower substantially cylindrical member a of each main double-link element a, and the flat bar i thereof extends between the overlapping end portions d and e within the upper member a" of the adjacent double link a. When the strap is in the released position, the side walls of the adjacent double links a are in close engagement with each other and the fiat bars i of the connecting elements 1 then extend substantially parallel to the straight arms d and rest closely against the inside of the enclosing end portion e of the upper member a", and, due to the oppositely directed spring action of portions d and e, arms at are clamped between these portions at such time so that the double-links a will be maintained in close engagement with each other, thus reducing the length of the strap to a minimum. When the strap is being expanded, the main double-links a, and the intermediate elements 1, which are thus connected with each other in zigzag formation, are pivoted apart and in the opposite directions. The fiat bars 1' of the connecting members 1 then turn counterclockwise against the spring action of portions d and e, and thereby force these portions apart. The spring force which is thus being accumulated inportions d and e, then tends to turn the fiat bar i of connecting elements 1 back to its original position substantially parallel to portion d, and it thus exerts a torque upon the flat bar i whereby, when the strap is released, the connecting elements 1 again turn in the clockwise direction and thereby move the upper and lower link me bets :1, a of one double-link a again into engagement with those of the adjacent double-link a.

Obviously, in place of or in addition to the use of the arm d as a spring member, a separate spring may be mounted within the upper cylindrical members a" to exert a spring pressure upon the fiat arm i under the action of the arm d. Also the bar i itself or in connection with the bracket arms g may be designed as a spring member, for example, by forming a torsion bar spring. Furthermore, the shape of the double-link elements at is by no means limited to a double-cylindrical shape, and particularly the upper link members a" which form the upper surface of the strap at least when the strap is in the contracted position may be of different shape or style to suit the fancy of different purchasers.

Thus, for example, the embodiment of the invention as shown in FIGS, 3 and 4 functions according to the same principle as the first-described embodiment, although in this case the main double-links k are of angular zigzag or stepped shape. Similar to the constriction b on the d0uble-links a as shown in FIG. 1, the double-links k are bent so as to form a constriction intermediate their upper and lower portions k and k". These upper and lower portions are each of substantially rectangular shape in cross section, as shown particularly by the double-link k farthest to the right in FIG. 3, and they are disposed at two different levels and substantially parallel to each other. The lower portion k has a lower flangelike side wall m, a bottom wall n, a second side wall 0, and atop wall p, while the upper link portion k" consists of a side wall m", a top wall n", a second side wall 0 which is slightly higher at its lower end than the opposite side wall m", and a lower wall p". The two superimposed side walls m and m" are slightly offset laterally relative to each other so that an intermediate gap will be formed between the vertical planes drawn along the adjacent edges of walls m and m", in which the vertical portion q of an angular arm q-r extends downwardly from the inner end of the lower wall p", while its horizontal arm portion r then extends substantially parallel to the bottom wall 11 of the lower link portion k. The wall portions 0", p", q, and r are bent so as to have an initial spring tension which tends to press the arm r downwardly and against the bottom wall n of the lower link portion k.

The connecting elements s form brackets of angular, substantially U-shaped design. The two parallel arms I and t project from the central arm s thereof into the superimposed link portions k and k" of two adjacent double-links k, and the lower arm I is interposed between the arm r and the bottom wall 11'. The spring pressure exerted by the arms r upon the arms t of connecting brackets s therefore tends to pivot the brackets to a vertical position and thereby tends to draw the adjacent main links k toward each other so that, when the strap is re leased, the wall portions 0 of the upper link portions k" move toward and into engagement with the wall portions m", while the wall portion 0' of the lower link portions k move toward and into engagement with the low flangelike wall portion m. When, on the other hand, the strap,

is being expanded and the main links k are drawn apart from each other, the connecting brackets s will be pivoted from their vertical rest position against the spring action of the entire spring arm 0", p", r of each main link k to the position shown in FIG. 3 by all except the righthand connecting element s. The spring force which is thus accumulated will then return the connecting brackets s to their normal vertical position when the strap is released, so that the latter will again be contracted to its minimum length.

The U-shaped connecting brackets s may be retained or secured within the main links k in any suitable manner. Thus, for example, in the embodiment of the invention as shown in FIGS. 3 and 4, the lower arm I of the U-shaped connecting bracket s is provided with a flange v which projects upwardly and into an aperture 11 of the arm r of the main link k, while the upper arm t" has an extension x which projects toward the left into an aperture w in the side wall 0" of the main link k. The projecting portions v and x are always automatically maintained in engagement within the apertures u and w, respectively, by the spring pressure of the spring arm 0", p", q, r acting upon the lower arm t of the connecting members s, and by the pivotal movement of the latter which is produced by such spring pressure.

Suitable means may also be provided to cover up the open ends of the links. Thus, for example, as illustrated in dotted lines in FIG. 1, the side arms g of the connecting elements may be made of a shape similar to the link elements a but without any central constriction b. In such case, the open ends, as well as the split between the portions 0 and 2 will be covered, and the strap will have a closed appearance even when looked upon at the narrow sides thereof.

though in the two embodiments of the invention, as shown in the drawings, the links and connecting elements a and f, and k and s, respectively, are of relatively great length transversely to the strap and their upper ornamental surfaces are parallel to each other as seen from the top, while the zigzag arrangement of the links and connecting elements will be noticeable only when the strap is viewed at the narrow sides thereof, the links and connecting elements may also be made very short and so as to extend at right angles to the formerly described embodiments so that the upper ornamental surface of the strap will then show the zigzag structure, while the longitudinal sides of the strap when in the contracted position will show an unbroken slightly undulated or fiat surface.

Although my invention has been illustrated and described with reference to the preferred embodiments thereof, I wish to have it understood that it is in no way limited to the details of such embodiments, but is capable of numerous modifications within the scope of the ap pended claims.

Having thus fully disclosed my invention, what I claim 1. An elastic link strap comprising: a plurality of link elements of substantially elongated shape transversely thereof and each forming a pair of opposite hollow portions integrally connected with each other, said opposite portions being disposed substantially in two different parallel planes, and those at one side of the link elements being superimposed to those at the other side at least when said strap is in the released position, intermediate connecting elements having opposite lateral parts, one of which is pivotally connected at one side to the first portion at one side of each link element and having at least one substantially flat bar at the opposite side, and a spring arm integral with and forming a free end of said first portion of each link element, and extending into the second portion thereof, and being overlapped by and pressing toward a free end of said second portion, said flat bar being interposed between said spring arm and said overlapping end of an adjacent link element and being disposed at an angle to said spring arm when said strap is in the expanded position, and substantially parallel to said spring arm when said strap is in the released position, said spring arm acting upon said flat bar tending to pivot'the same to a position parallel to said spring arm and thereby toward said second portion of said link element, and thus to draw the adjacent link elements toward each other. 7

2. An elastic link strap comprising: a plurality of link elements of substantially elongated shape transversely thereof and each forming a pair of opposite hollow portions integrally connected with each other, said opposite portions being disposed substantially in two different parallel planes, and those at one side of the link elements being superimposed to those at the other side at least when said strap is in the released position, each of said link elements having a constriction intermediate said hollow portions, intermediate connecting elements each having end portions embracing the outer ends of said link elements, and at least one pivot member at one side of each connecting element engaging into the first hollow portion or" said link elements and being retained therein by said constriction and having at least one substantially flat bar at the opposite side, and a spring arm integral with and forming a free end of said first portion of each link element, and extending into the second portion thereof, and being overlapped by and pressing toward a free end of said second portion, said fiat bar being interposed between said spring arm and said overlapping end of an adjacent link element and being disposed at an angle to said spring arm when said strap is in the expanded position, and substantially parallel to said spring arm when said strap is in the released position, said spring arm acting upon said flat bar tending to pivot the same to a position parallel to said spring arm and thereby toward said second portion of said link element, and thus to draw the adjacent link elements toward each other.

3. An elastic link strap comprising: a plurality of link elements having open outer ends and being of substantially elongated shape transversely thereof and each form ing a pair of opposite hollow portions, each of said portions being of substantially cylindrical shape and integrally connected with each other by an inwardly bent trough-shaped portion, said cylindrical portions being disposed substantially in two different parallel planes, and those at one side of the link elements being superimposed to those at the other side at least when said strap is in the released position, each of said cylindrical portions being split apart at one side to form, at its interior side, a gap, said gaps facing toward each other, the free end of the first cylindrical portion being extended and forming a substantially flat spring arm projecting under spring tension through said gap into the second cylindrical portion and being overlapped by and pressing toward a free end of the second cylindrical portion, and intermediate framelike connecting elements connecting said first portion of one link element with the second portion of the adjacent link element so as to produce a zigzag formation of said elements when viewed at the ends thereof, said connecting elements each having a pair of outer end portions embracing the open outer ends of one of said link elements and each having at least one pivot member at one side engaging into said first portion of said one link element and being retained therein by said trough-shaped portion, and having a substantially flat crossbar at the other side and connecting the outer end portions thereof, said crossbar being interposed between said spring arm and said overlapping end of an adjacent link element and being disposed at an angle to said spring arm when said strap is in the expanded position, and substantially parallel to said spring arm when said strap is in the released position, said spring arm and said overlapping end resiliently acting from opposite directions upon said flat crossbar tending to pivot the same to a position parallel to said spring arm and thereby toward said second portion of said link element, and thus to draw the adjacent link ele ments toward each other.

' 4. An elastic link strap as defined in claim 3 wherein said pair of outer end portions of said framelike connecting elements gradually converge from one wider side toward the other narrower side, said pivot member comprising a tubular member connecting said wider sides and pivot-ally mounted Within said first cylindrical portion of one link element, said flat crossbar connecting said narrower sides of said connecting elements.

5. An elastic link strap comprising: a plurality of link elements of substantially elongated shape transversely thereof and each being made of a single strip of sheet metal and forming a pair of opposite hollow portions, each of said portions being of substantially rectangular shape and having top, bottom, and side walls, the bottom wall of the first portion and the top wall of the second portion being split apart near one lateral edge so as to form a gap, said pair of opposite hollow portions being integrally connected with each other adjacent :to one edge of each gap and disposed in a steplike oifset relation to each other in the longitudinal direction of said strap and in two dilferent parallel planes so that the first portion of one link element is superimposed .to the second portion of an adjacent link element at least when said strap is in the released position, said first portion having a substantially rectangular extension at the free bottom edge there of and extending into the second portion through the gap in the top wall thereof and then in a direction substantially parallel to the bottom wall thereof, said extension forming a spring arm pressing in the direction toward said last bottom wall, and at least one bracketlike member connecting adjacent link elements with each other and having outer end portions embracing the open outer ends of said link elements, and at least one arm extending from said outer end portions into the open ends of said first portion of one link element, and at least one flat arm extending from said outer end portions into the open ends of the second portion of the adjacent link element and between said bottom wall thereof and said spring arm in said second portion, said fiat arm being disposed at an angle to said spring arm when said strap is in the ex panded position, and substantially parallel to said spring arm and said bottom wall when said strap is in the released position, said spring arm pressing upon said fiat arm tending to pivot the same to a position parallel to said spring arm and said bottom wall, and thereby to pivot said first arm in said first portionof one link element against one side wall thereof to urge the same toward the opposite side wall of the first portion of the adjacent link element.

6. An elastic link strap as defined in claim 5 wherein said bracketlike connecting member is substantially U shaped and both arms of said member are flat and substantially parallel to each other, and means on each con+ necting member for maintaining said arms within said link elements.

7. An elastic link strap as defined in claim 5 wherein said arms of said bracketli'ke connecting member are substantially parallel to each other, and wherein said last mentioned side wall and said spring arm each havean aperture therein, and each of the edges of said arms which are pivoted upwardly when said strap is being expanded has a projection thereon extending into said apertures to maintain said arms Within said link elements.

References Cited in the file of this patent UNITED STATES PATENTS 757,772 Rodenberg Apr. 19, 1904 1,089,931 Loog Mar. 10, 1914 2,430,777 Miller Nov. 17, 1947 2,689,450 Stiegele Sept. 21, 1954 FOREIGN PATENTS 421,157 France Dec. 14, 1910 

1. AN ELASTIC LINK STRAP COMPRISING: A PLURALITY OF LINK ELEMENTS OF SUBSTANTIALLY ELONGATED SHAPE TRANSVERSELY THEREOF AND EACH FORMING A PAIR OF OPPOSITE HOLLOW PORTIONS INTEGRALLY CONNECTED WITH EACH OTHER, SAID OPPOSITE PORTIONS BEING DISPOSED SUBSTANTIALLY IN TWO DIFFERENT PARALLEL PLANES, AND THOSE AT ONE SIDE OF THE LINK ELEMENTS BEING SUPERIMPOSED TO THOSE AT THE OTHER SIDE AT LEAST WHEN SAID STRAP IS IN THE RELEASED POSITION, INTERMEDIATE CONNECTING ELEMENTS HAVING OPPOSITE LATERAL PARTS, ONE OF WHICH IS PIVOTALLY CONNECTED AT ONE SIDE TO THE FIRST PORTION AT ONE SIDE OF EACH LINK ELEMENT AND HAVING AT LEAST ONE SUBSTANTIALLY FLAT BAR AT THE OPPOSITE SIDE, AND A SPRING ARM INTEGRAL WITH AND FORMING A FREE END OF SAID FIRST PORTION OF EACH LINK ELEMENT, AND EXTENDING INTO THE SECOND PORTION THEREOF, AND BEING OVERLAPPED BY AND PRESSING TOWARD A FREE END OF SAID SECOND PORTION, SAID FLAT BAR BEING INTERPOSED BETWEEN SAID SPRING ARM AND SAID OVERLAPPING END OF AN ADJACENT LINK ELEMENT AND BEING DISPOSED AT AN ANGLE TO SAID SPRING ARM WHEN SAID STRAP IS IN THE EXPANDED POSITION, AND SUBSTANTIALLY PARALLEL TO SAID SPRING ARM WHEN SAID STRAP IS IN THE RELEASED POSITION, SAID SPRING ARM ACTING UPON SAID FLAT BAR TENDING TO PIVOT THE SAME TO A POSITION PARALLEL TO SAID SPRING ARM AND THEREBY TOWARD SAID SECOND PORTION OF SAID LINK ELEMENT, AND THUS TO DRAW THE ADJACENT LINK ELEMENTS TOWARD EACH OTHER. 